1. Field of the Invention
This invention relates to a micro device and a method for fabricating the micro device. As the micro device are exemplified a thin film magnetic head, a thin film inductor, a semiconductor device, a thin film sensor, a thin film actuator, or a composite device equipped with one or some of the thin film devices.
2. Related Art Statement
A thin film magnetic head including a writing element and a reading element is a type of micro device. Normally, the writing head includes a first and a second magnetic layers, the forefronts of which constitute a magnetic pole via a gap layer in an air bearing surface (herein, abbreviated as an “ABS”). The first and the second magnetic layers are magnetically joined at a back gap portion remote from the ABS to complete a magnetic circuit. Then, a planer thin film coil is arranged to wind around the back gap portion within a plane parallel to the first and the second magnetic layers and perpendicular to the ABS.
In the use of the planer thin film coil, the coil length is elongated inevitably, so that the impedance of the thin film coil can not be decreased sufficiently, and the high frequency performance of the thin film coil can not be improved sufficiently.
In the fabrication of the thin film coil, conventionally, a frame-plating method used to be employed, which is typically disclosed in the Japanese Patent examined application No. 56-36706. In this fabrication, a frame-plating treatment is carried out through a resist frame which is later removed, so that the distance between the adjacent coil turns is determined by the bottom width of the each resist frame. Therefore, the density of the coil turn can not be increased sufficiently and the magnetic efficiency of the thin film coil can not be improved sufficiently. Also, the thin film coil can not be down-sized sufficiently.
A new type of thin film magnetic head is disclosed in Japanese Patent Application Laid-open No. 2001-93113 where the winding center axis of the thin film coil is shifted vertically by 90 degrees from the normal horizontal arrangement as mentioned above, to shorten the magnetic path of the thin film coil and to reduce the loss of the eddy current, and thus, to enhance the high frequency performance of the thin film magnetic head.
In this case, too, the frame-plating method is employed in the fabrication of the thin film coil, and the distance between the adjacent coil turns is determined by the bottom width of the resist frame. Therefore, the density of the coil turn can not be increased sufficiently and the magnetic efficiency of the thin film coil can not be improved sufficiently. Also, the thin film coil can not be down-sized sufficiently.